A Contribution to the Mechanism of Elimination of Dimethylformamide and Dimethylamine by a Heterogenous Culture of Microorganisms

In a batch experiment with activated sludge from a large-scale plant the hydrolytical and biochemical degradation of dimethylformamide (DMF) and its reaction product dimethylamine (DMA) and the conversion connected with this under aerobic and anaerobic conditions is investigated. Parallel to the hydrolysis of DMF the biochemical degradation of DMA occurs. The extensive conversion of these substrates is followed by the nitrification of the ammoniumions formed, and under subsequent anaerobic conditions with methanol as the carbon source also denitrification can be achieved. If the oxygen supply of the activated sludge is insufficient, however, also DMA can be used as a carbon source for denitrification, ammonium-ions being released from DMA in addition. In the batch experiment the elimination rates referred to nitrogen were 7 … 14 mg/g · h for DMF, 0.8 … 1.7 mg/g · h for DMA, 0.3 … 0.6 mg/g · h for NH and 0.4 to 1.3 mg/g · h for nitrate in the presence of methanol. DMF and DMA are obviously not suitable as the only carbon source for denitrification.